The present invention relates to a series of new chemical agents that demonstrate anti-proliferative effects against human endothelial cells for the treatment of a variety of diseases including cancer, in addition to an inhibitory effect directly on cancer cells for the treatment of solid tumors. More particularly, the present invention relates to molecules that demonstrate anti-proliferative capabilities against human endothelial cells and several epithelial cancer cells and their applications in treating a variety of disease states.
Cancer is a disease state characterized by the uncontrolled proliferation of genetically altered tissue cells. There have been several chemotherapeutic approaches targeted against such proliferation including alkylating agents, antimitotics, antimetabolites, and antibiotics. These act preferentially on rapidly proliferating cells including cancer cells. Hormonal therapy with anti-estrogens or anti-androgens is another approach to attacking cancer cells that work by inhibiting the proliferative action of the required hormone. Although anti-cancer agents fall into specific classifications, it is not uncommon for agents to act by multiple modes of action. For example, the anti-estrogen tamoxifen has been shown to have anti-proliferative activity on cancer cells and endothelial cells by an estrogen independent mechanism. Taxol, an antimitotic agent acting on microtubules has also demonstrated antiangiogenic properties, possibly by inducing apoptosis through Bcl-2 phosphorylation.
Angiogenesis, the formation of new blood vessels, is a fundamental biological process involved in wound healing, tissue regeneration, embryogenesis and the female reproductive cycle. Blood vessel walls are formed by endothelial cells that have the ability to divide and migrate under specific stimuli, such as growth factors. The creation of new blood vessels follows a specific set of tightly regulated steps. Briefly, endothelial cells are stimulated by factors secreted by surrounding cells and secrete enzymes such as matrix metalloproteinases that break down the extra-cellular matrix and basement membrane, thus creating a space for the cells to migrate into and establish themselves. The endothelial cells then organize into hollow tubes that eventually form a new vascular network of blood vessels providing surrounding cells with nutrients and oxygen and the ability to eliminate toxic metabolic waste products. Under normal physiological conditions endothelial cells are dormant unless triggered to proliferate in localized parts of tissues. Many diseases are associated with the inappropriate proliferation of endothelial cells including arthritis, psoriasis, arteriosclerosis, diabetic retinopathy, and cancer.
In order for a tumor to grow beyond a few million cells, typically more than 1 or 2 mm3 in volume, an increase in vascularization is required. Cells that are too distant from blood vessels cannot survive because of poor nutrient and oxygen supply. Clinically, tumors that are highly vascularized are the most metastatic and difficult to treat. It is also known that tumor cells produce and secrete the factors necessary for angiogenesis. It is widely held that agents inhibiting angiogenesis through direct competition with angiogenic factors, or by some other mechanism, would have a major clinical benefit in the treatment of many types of cancer and other diseases associated with inappropriate angiogenesis.
Many therapeutic agents are being targeted for development based on a variety of targeting strategies. One strategy is the use of natural inhibitors of angiogenesis such as angiostatin and endostatin. Another strategy is the use of agents that block the receptors required to stimulate angiogenesis, such as antagonists to the vitronectin receptor. Yet a third strategy is the inhibition of specific enzymes which allow new blood vessels to invade surrounding tissues, for example, inhibitors of matrix metalloproteinases.
Angiogenesis is an attractive therapeutic target for cancer treatment due to its selectivity of action. Blood vessels in growing tumors are rapidly proliferating and being replaced, whereas blood vessels in most normal tissues are static. This rapid turnover is believed to be the physiological difference that will allow the selective targeting of blood vessels in the tumor by anti-angiogenic agents. Anti-angiogenesis is also less likely to pose a drug resistance problem compared to conventional chemotherapeutics. Tumor cells are prone to mutations that render them resistant to standard chemotherapy. Since anti-angiogenic agents target normal but rapidly proliferating endothelial cells that are not genetically unstable, resistance to anti-angiogenic agents is not a major concern.
Anti-angiogenic therapy will likely be very effective at suppressing tumor growth by denying tumors a blood supply. However, anti-angiogenic therapy may prove more effective in combination with other therapies aimed directly at the tumor cells. Chemical agents that demonstrate both anti-angiogenic and tumor directed properties would obviously be greatly desired. There thus remains a need to develop a series of chemical agents that demonstrate anti-proliferative effects against human endothelial cells for the treatment of a variety of diseases including cancer, in addition to an inhibitory effect directly on cancer cells for the treatment of solid tumors.
The present invention seeks to meet these and other needs.
The present description refers to a number of documents, the content of which is herein incorporated by reference in their entirety.
It has now been discovered that certain dibenzo[c]chromen-6-one derivatives have anti-proliferative abilities against both human endothelial cells and epithelial cancer cell lines and can be made as set forth herein.
The present invention relates to a series of chemical agents that demonstrate anti-proliferative effects against human endothelial cells for the treatment of a variety of diseases including cancer, in addition to an inhibitory effect directly on cancer cells for the treatment of solid tumors.
The present invention also relates to anti-cancer molecules that are derivatives of dibenzo[c]chromen-6-one.
As well, the present invention relates to a therapeutic composition of molecules useful in the treatment of cancer and other diseases, characterized by the undesired proliferation of endothelial or epithelial cells such as, but not limited to, pathological tissue growth, psoriasis, diabetic retinopathy, rheumatoid arthritis, hemangiomas, solid tumor formation and other malignancies.
In accordance with one embodiment of the present invention, there is provided a pharmaceutical composition, comprising a therapeutically effective amount of anti-cancer molecules specified herein. As used herein, the terms R1, R2, R3 and R4 refer to effective functional groups, whose location on the dibenzo[c]chromen-6-one backbone is illustrated below by Formula I: 
wherein R1 is one of, but not limited to the following: H, OH or OR3; wherein certain preferred substituents at R2 are one of, but not limited to the following: 
wherein certain preferred substituents at R3 are one of, but not limited to the following: a lower alkyl chain ranging from 1 to 8 carbons; and wherein R4 is selected from the group consisting of: hydrogen, hydroxy, methoxy, ethoxy and trifluoroethoxy.
In accordance with the present invention, there is therefore provided a compound of Formula I, or a pharmaceutically acceptable salt or ester thereof, 
wherein R1 represents a substituent selected from the group consisting of H, OH and OR3; wherein R2 represents a substituent selected from the group consisting of 
wherein R3 is a C1-8 lower alkyl chain and wherein R4 is selected from the group consisting of: hydrogen, hydroxy, methoxy, ethoxy and trifluoroethoxy.
In accordance with the present invention, there is also provided a process for the preparation of a compound of Formula 1.5 involving the reaction of a molecule of Formula 1.4: 
wherein R1 represents a substituent selected from the group consisting of H, OH and OR3; wherein R2 represents a substituent selected from the group consisting of 
wherein R3 is a C1-8 lower alkyl chain; and wherein R4 is selected from the group consisting of: hydrogen, hydroxy, methoxy, ethoxy and trifluoroethoxy; with a reagent mixture comprising SOCl2 and AlCl3, followed by the recovery of the compound of Formula 1.5 from the reaction mixture.
In accordance with the present invention, there is also provided a process for the preparation of a compound of Formula III, wherein R1 is OR3, wherein R2 is 
wherein R3 is CH3 and wherein R4 is a methoxy group; involving the reaction of a compound of Formula 1.8: 
with a reagent mixture comprising SOCl2 and AlCl3, followed by the recovery of the compound of Formula III from the reaction mixture.
In accordance with the present invention, there is also provided a process for the preparation of a compound of Formula II, wherein R1 is OR3, wherein R2 is 
wherein R3 is CH3 and wherein R4 is a methoxy group; involving the reaction of a compound of Formula 1.9: 
with a reagent mixture comprising HOCH2CH2OH and p-TsOH, followed by the recovery of the compound of Formula II from the reaction mixture.
In accordance with the present invention, there is provided a pharmaceutical composition comprising the compound represented by Formula I and at least one pharmaceutically acceptable carrier.
In accordance with the present invention, there is also provided a process for the preparation of anti-cancer agents of Formula I, involving the reaction of a molecule of Formula 1.4, as previously defined, with a reagent system comprising SOCl2 and AlCl3, followed by the recovery of the anti-cancer agent of Formula I from the reaction mixture.
In accordance with the present inventions there is also provided a process for the preparation of an anti-cancer agent of Formula III, wherein R1 is OR3, wherein R2 is 
wherein R3 is CH3; and R4 is a methoxy group; involving the reaction of a compound of Formula 1.8, as previously defined, with a reagent system comprising SOCl2 and AlCl3, followed by the recovery of the anti-cancer agent of Formula III from the reaction mixture.
Finally, in accordance with the present invention there is provided a process for the preparation of an anti-cancer agent of Formula II, wherein R1 is OR3, wherein R2 is 
wherein R3 is CH3, and wherein R4 is a methoxy group; involving the reaction of a compound of Formula 1.9, as previously defined, with a reagent mixture comprising HOCH2CH2OH and p-TsOH, followed by the recovery of the anti-cancer agent of Formula II from the reaction mixture.
Unless defined otherwise, the scientific and technological terms and nomenclature used herein have the same meaning as commonly understood by a person of ordinary skill in the art. Generally, procedures such as recovering axe2x80x94or more compounds from a reaction mixture are common methods used in the art. Such standard techniques can be found in reference manuals such as for example Gordon and Ford (The Chemist""s Companion: A Handbook of Practical Data, Techniques and References, John Wiley and Sons, New York, N.Y., 1972).
The present description refers to a number of routinely used chemical terms. Nevertheless, definitions of selected examples of such terms are provided for clarity and consistency.
As used herein, the terminology xe2x80x9cpharmaceutical compositionxe2x80x9d or xe2x80x9cpharmaceutical formulationxe2x80x9d, well known in the art, are used interchangeably.
As used herein, the terminology xe2x80x9crecoveringxe2x80x9d, well known in the art, refers to a molecule having been isolated from other components of a reaction mixture.
The present invention comprises the genus of compounds represented by Formula I, useful in the treatment of cancer and other diseases characterized by the undesired proliferation of endothelial or epithelial cells such as, but not limited to, pathological tissue growth, psoriasis, diabetic retinopathy, rheumatoid arthritis, hemangiomas, solid tumor formation and other malignancies.
It will be appreciated by those skilled in the art that reference herein to treatment extends to prophylactic treatment as well as the treatment of established diseases or symptoms. It will be further appreciated, that the amount of a compound of the invention required for use in treatment, will vary with the nature of the condition being treated, the age and condition of the patient and will ultimately be at the discretion of the attending physician or medical practitioner. In general however, doses employed for adult human treatment will typically be in the range of 0.001 mg/kg to about 100 mg/kg per day. The desired dose may conveniently be presented in a single dose or as divided doses administered at appropriate intervals such as for example two, three, four or more sub-doses per day. It will be further appreciated by those skilled in the art that compounds of Formula I may be administered alone or in conjunction with standard tumor therapy, such as chemotherapy or radiation therapy.
The present invention also provides for novel pharmaceutical compositions of the compounds of Formula I. While it is possible that compounds of the present invention may be therapeutically administered as the raw chemical, it is preferable to present the active ingredient as a pharmaceutical formulation. Accordingly, the present invention further provides for pharmaceutical formulations comprising a compound of Formula I or a pharmaceutically acceptable salt or ester thereof together with one or more pharmaceutically acceptable carriers and, optionally, other therapeutic and/or prophylactic ingredients. The carrier(s) must be xe2x80x9cacceptablexe2x80x9d in the sense of being compatible with the other ingredients of the formulation and not be deleterious to the recipient thereof.
Formulations of the present invention, for the treatment of the indicated diseases, may be administered in standard manner, such as orally, parenterally, subligually, transdermally, rectally or via inhalation. For oral administration, the composition may take the form of tablets or lozenges, formulated in a conventional manner. For example, tablets and capsules for oral administration may contain conventional excipients such as binding agents, (for example, syrup, accacia, gelatin, sorbitol, tragacanth, mucilage of starch or polyvinylpyrrolidone), fillers (for example, lactose, sugar, microcrystalline cellulose, maize-starch, calcium phosphate or sorbitol), lubricants (for example, magnesium stearate, stearic acid, talc, polyethylene glycol or silica), disintegrants (for example, potato starch or sodium starch glycollate) and wetting agents such as sodium lauryl sulphate. The tablets may be coated according to methods well known in the art.
Alternatively, the compounds of the present invention may be incorporated into oral liquid preparations such as aqueous or oily suspensions, solutions, emulsions, syrups or elixirs. Moreover, formulations containing these compounds may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents such as sorbitol syrup, methyl cellulose, glucose/sugar syrup, gelatin, hydroxyethylcellulose, carboxymethyl cellulose, aluminum stearate gel or hydrogenated edible fats; emulsifying agents such as lecithin, sorbitan mono-oleate or acacia; non-aqueous vehicles (which may include edible oils) such as almond oil, fractionated coconut oil, oily esters, propylene glycol or ethyl alcohol; and preservatives such as methyl or propyl p-hydroxybenzoates or sorbic acid.
Such preparations may also be formulated as suppositories, e.g., containing conventional suppository bases such as cocoa butter or other glycerides. Compositions for inhalation can be typically provided in the form of a solution, suspension or emulsion that may be administered as a dry powder or in the form of an aerosol using a conventional propellant such as dichlorodifluoromethane or trichlorofluoromethane. Typical transdermal formulations comprise a conventional aqueous or non-aqueous vehicle, such as creams, ointments, lotions or pastes or are in the form of a medicated plaster, patch or membrane.
Additionally, compositions of the present invention may be formulated for parenteral administration by injection or continuous infusion. Formulations for injection may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilising and/or dispersing agents. Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle (e.g., sterile, pyrogen-free water) before use.
Compositions of the present invention may be formulated for nasal administration. Such formulations may comprise the selected compounds of the present invention and a non-toxic pharmaceutically acceptable nasal carrier. Suitable non-toxic pharmaceutically acceptable nasal carriers for use in the compositions of the present invention will be apparent to those skilled in the art of nasal pharmaceutical formulations. Obviously the choice of suitable carriers will depend on the exact nature of the particular nasal dosage form desired, as well as on the identity of the active ingredient(s). For example, whether the active ingredient(s) are to be formulated into a nasal solution (for use as drops or spray), a nasal suspension, a nasal ointment or a nasal gel. Preferred nasal dosage forms are solutions, suspensions and gels, which contain a major amount of water (preferably purified water) in addition to the active ingredient(s). Minor amounts of other ingredients such as pH adjusters (e.g., a base such as NaOH), emulsifiers or dispersing agents (e.g. polyoxyethylene 20 sorbitan mono-oleate), buffering agents, preservatives, wetting agents and gelling agents (e.g. methylcellulose) may also be present. Also, a sustained release composition (e.g. a sustained release gel) can be readily prepared.
The composition according to the present invention may also be formulated as a depot preparation. Such long acting formulations may be administered by implantation (for example, subcutaneously or intramuscularly) or by intramuscular injection. Accordingly, the compounds of the present invention may be formulated with suitable polymeric or hydrophobic materials (such as an emulsion in an acceptable oil), ion exchange resins or, as sparingly soluble derivatives or sparingly soluble salts.